#include <bits/stdc++.h>

using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");
#define cin fin
#define cout fout

const int Nmax = 100001;
vector <int>g[Nmax];
queue <int>q;
int n,x,y,d[Nmax],k,aux;

void bfs(int nod)
{
  memset(d,-1,sizeof(d));
  q.push(nod);
  d[nod] = 0;

  while(!q.empty())
  {
    nod = q.front();
    q.pop();
    for(int i=0;i<(int)g[nod].size();i++)
    {
      int vecin = g[nod][i];
      if(d[vecin]==-1)
      {
        d[vecin] = d[nod]+1;
        q.push(vecin);
        aux = vecin;
      }
    }
  }
}
int main()
{
    cin>>n;
    for(int i=1;i<n;i++)
    {
      cin>>x>>y;
      g[x].push_back(y);
      g[y].push_back(x);
    }
    bfs(11);
    bfs(aux);
    aux = 0;
    for(int i=1;i<=n;i++)
    aux = max(aux,d[i]);

    cout<<aux+1;
    return 0;
}